<!DOCTYPE html> <html> <head> <style> #rel { position: relative; margin: 2px; padding: 0; } .fixed, .abs { position: fixed; margin: 0; padding: 0; top: 25px; left: 25px; width: 50px; height: 50px; background-color: green; } #bad { background-color: red; } </style> </head> <body> The green square should completely cover the red square. <div class="abs" id="bad"></div> <table> <caption id="rel"><div class="fixed"></div></caption> </table> </body> </html>